1 /* 2 * NDEF(NFC Data Exchange Format) routines for Wi-Fi Protected Setup 3 * Reference is "NFCForum-TS-NDEF_1.0 2006-07-24". 4 * Copyright (c) 2009, Masashi Honma <honma (at) ictec.co.jp> 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License version 2 as 8 * published by the Free Software Foundation. 9 * 10 * Alternatively, this software may be distributed under the terms of BSD 11 * license. 12 * 13 * See README and COPYING for more details. 14 */ 15 16 #include "includes.h" 17 #include "common.h" 18 #include "wps/wps.h" 19 #include "wps/wps_i.h" 20 21 #define FLAG_MESSAGE_BEGIN (1 << 7) 22 #define FLAG_MESSAGE_END (1 << 6) 23 #define FLAG_CHUNK (1 << 5) 24 #define FLAG_SHORT_RECORD (1 << 4) 25 #define FLAG_ID_LENGTH_PRESENT (1 << 3) 26 #define FLAG_TNF_RFC2046 (0x02) 27 28 struct ndef_record { 29 u8 *type; 30 u8 *id; 31 u8 *payload; 32 u8 type_length; 33 u8 id_length; 34 u32 payload_length; 35 u32 total_length; 36 }; 37 38 static char wifi_handover_type[] = "application/vnd.wfa.wsc"; 39 40 static int ndef_parse_record(u8 *data, u32 size, struct ndef_record *record) 41 { 42 u8 *pos = data + 1; 43 44 if (size < 2) 45 return -1; 46 record->type_length = *pos++; 47 if (data[0] & FLAG_SHORT_RECORD) { 48 if (size < 3) 49 return -1; 50 record->payload_length = *pos++; 51 } else { 52 if (size < 6) 53 return -1; 54 record->payload_length = ntohl(*(u32 *)pos); 55 pos += sizeof(u32); 56 } 57 58 if (data[0] & FLAG_ID_LENGTH_PRESENT) { 59 if ((int) size < pos - data + 1) 60 return -1; 61 record->id_length = *pos++; 62 } else 63 record->id_length = 0; 64 65 record->type = record->type_length == 0 ? NULL : pos; 66 pos += record->type_length; 67 68 record->id = record->id_length == 0 ? NULL : pos; 69 pos += record->id_length; 70 71 record->payload = record->payload_length == 0 ? NULL : pos; 72 pos += record->payload_length; 73 74 record->total_length = pos - data; 75 if (record->total_length > size) 76 return -1; 77 return 0; 78 } 79 80 81 static struct wpabuf * ndef_parse_records(struct wpabuf *buf, 82 int (*filter)(struct ndef_record *)) 83 { 84 struct ndef_record record; 85 int len = wpabuf_len(buf); 86 u8 *data = wpabuf_mhead(buf); 87 88 while (len > 0) { 89 if (ndef_parse_record(data, len, &record) < 0) { 90 wpa_printf(MSG_ERROR, "NDEF : Failed to parse"); 91 return NULL; 92 } 93 if (filter == NULL || filter(&record)) 94 return wpabuf_alloc_copy(record.payload, 95 record.payload_length); 96 data += record.total_length; 97 len -= record.total_length; 98 } 99 wpa_printf(MSG_ERROR, "NDEF : Record not found"); 100 return NULL; 101 } 102 103 104 static struct wpabuf * ndef_build_record(u8 flags, void *type, 105 u8 type_length, void *id, 106 u8 id_length, void *payload, 107 u32 payload_length) 108 { 109 struct wpabuf *record; 110 size_t total_len; 111 int short_record; 112 u8 local_flag; 113 114 short_record = payload_length < 256 ? 1 : 0; 115 116 total_len = 2; /* flag + type length */ 117 /* payload length */ 118 total_len += short_record ? sizeof(u8) : sizeof(u32); 119 if (id_length > 0) 120 total_len += 1; 121 total_len += type_length + id_length + payload_length; 122 record = wpabuf_alloc(total_len); 123 if (record == NULL) { 124 wpa_printf(MSG_ERROR, "NDEF : Failed to allocate " 125 "record for build"); 126 return NULL; 127 } 128 129 local_flag = flags; 130 if (id_length > 0) 131 local_flag |= FLAG_ID_LENGTH_PRESENT; 132 if (short_record) 133 local_flag |= FLAG_SHORT_RECORD; 134 wpabuf_put_u8(record, local_flag); 135 136 wpabuf_put_u8(record, type_length); 137 138 if (short_record) 139 wpabuf_put_u8(record, payload_length); 140 else 141 wpabuf_put_be32(record, payload_length); 142 143 if (id_length > 0) 144 wpabuf_put_u8(record, id_length); 145 wpabuf_put_data(record, type, type_length); 146 wpabuf_put_data(record, id, id_length); 147 wpabuf_put_data(record, payload, payload_length); 148 return record; 149 } 150 151 152 static int wifi_filter(struct ndef_record *record) 153 { 154 if (record->type_length != os_strlen(wifi_handover_type)) 155 return 0; 156 if (os_memcmp(record->type, wifi_handover_type, 157 os_strlen(wifi_handover_type)) != 0) 158 return 0; 159 return 1; 160 } 161 162 163 struct wpabuf * ndef_parse_wifi(struct wpabuf *buf) 164 { 165 return ndef_parse_records(buf, wifi_filter); 166 } 167 168 169 struct wpabuf * ndef_build_wifi(struct wpabuf *buf) 170 { 171 return ndef_build_record(FLAG_MESSAGE_BEGIN | FLAG_MESSAGE_END | 172 FLAG_TNF_RFC2046, wifi_handover_type, 173 os_strlen(wifi_handover_type), NULL, 0, 174 wpabuf_mhead(buf), wpabuf_len(buf)); 175 } 176
